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<head><meta charset="utf-8"><title>rustc-bisect · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html">rustc-bisect</a></h3>

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<a name="164180880"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164180880" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164180880">(Apr 25 2019 at 15:31)</a>:</h4>
<p>was talking with <span class="user-mention" data-user-id="116009">@nikomatsakis</span> about rustc-bisect after I've heard of it during the weekly meeting</p>



<a name="164180986"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164180986" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164180986">(Apr 25 2019 at 15:32)</a>:</h4>
<p>would be nice to be able to run <code>cargo bisect-rustc</code> on the project itself</p>



<a name="164181474"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181474" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181474">(Apr 25 2019 at 15:37)</a>:</h4>
<p>(cc <span class="user-mention" data-user-id="116122">@simulacrum</span>)</p>



<a name="164181486"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181486" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181486">(Apr 25 2019 at 15:37)</a>:</h4>
<p>Yeah, so, I think cargo-bisect-rustc is awesome but could be made a lot simpler</p>



<a name="164181492"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181492" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181492">(Apr 25 2019 at 15:37)</a>:</h4>
<p>My "north star" is that when somebody reports a regression</p>



<a name="164181499"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181499" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181499">(Apr 25 2019 at 15:37)</a>:</h4>
<p>They should be able to go to their project</p>



<a name="164181514"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181514" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181514">(Apr 25 2019 at 15:37)</a>:</h4>
<p>And instead of doing <code>cargo build</code> do <code>cargo install cargo-bisect-rustc; cargo bisect-rustc</code></p>



<a name="164181535"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181535" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181535">(Apr 25 2019 at 15:37)</a>:</h4>
<p>and they should get a "report" they can paste into the bug report</p>



<a name="164181629"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181629" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181629">(Apr 25 2019 at 15:38)</a>:</h4>
<p>it would say something like:</p>
<hr>
<p>Regression occurred on <strong>nightly-2018-04-28</strong> and specifically PR <a href="https://github.com/rust-lang/rust/issues/12153" target="_blank" title="https://github.com/rust-lang/rust/issues/12153">#12153</a> (cc @authors of the pr, @rust-lang/compiler)</p>



<a name="164181642"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181642" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181642">(Apr 25 2019 at 15:38)</a>:</h4>
<p>Then there would be options to do more advanced stuff</p>



<a name="164181678"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181678" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181678">(Apr 25 2019 at 15:38)</a>:</h4>
<p>The way I imagine this working is a few things:</p>
<ul>
<li>First, we bisect using nightly builds -- but we assume the currently installed nightly is the end point, and we search exponentially backwards to find a start point</li>
</ul>



<a name="164181746"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181746" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181746">(Apr 25 2019 at 15:39)</a>:</h4>
<ul>
<li>Once we know the nightly where it went wrong, we checkout (into a temporary directory) <code>rust-lang/rust</code> and we use the SHA1-range for the nightly to get a PR range</li>
</ul>



<a name="164181753"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181753" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181753">(Apr 25 2019 at 15:39)</a>:</h4>
<ul>
<li>Then we bisect within the PRs, if possible</li>
</ul>



<a name="164181760"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181760" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181760">(Apr 25 2019 at 15:39)</a>:</h4>
<ul>
<li>Finally we emit the output</li>
</ul>



<a name="164181841"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181841" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181841">(Apr 25 2019 at 15:40)</a>:</h4>
<p>Ideally, we'd use GH API to include information in that output, like the list of PRs in the nightly etc, but</p>



<a name="164181957"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181957" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164181957">(Apr 25 2019 at 15:41)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="164186648"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164186648" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164186648">(Apr 25 2019 at 16:34)</a>:</h4>
<blockquote>
<p>and they should get a "report" they can paste into the bug report</p>
</blockquote>
<p>though maybe it takes a while to run :)</p>



<a name="164196581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164196581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164196581">(Apr 25 2019 at 18:25)</a>:</h4>
<p>I am happy to hand off ownership or review PRs but do not have bandwidth for this sort of overhaul myself</p>



<a name="164291300"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164291300" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164291300">(Apr 26 2019 at 19:34)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> I'm trying to find somebody else to do it, indeed :)</p>



<a name="164301713"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164301713" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164301713">(Apr 26 2019 at 22:04)</a>:</h4>
<p>It seems like what needs to happen is for <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> and I to sit down and kind of draw up a roadmap, eh? I could see this being a (potentially small) working group, though I think there might be enough work that 2 or 3 people could hack on it together</p>



<a name="164314222"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164314222" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#164314222">(Apr 27 2019 at 03:00)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> <span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="176930536"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/176930536" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#176930536">(Sep 30 2019 at 13:16)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> <a href="#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181486" title="#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/164181486">these are the comments I was referring to</a></p>



<a name="177257286"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257286" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257286">(Oct 03 2019 at 15:44)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> <span class="user-mention" data-user-id="116122">@simulacrum</span> FYI I'm going to take this task slowly meanwhile I'm doing other things</p>



<a name="177257353"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257353" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257353">(Oct 03 2019 at 15:45)</a>:</h4>
<p><span aria-label="thumbs up" class="emoji emoji-1f44d" role="img" title="thumbs up">:thumbs_up:</span></p>



<a name="177257363"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257363" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257363">(Oct 03 2019 at 15:45)</a>:</h4>
<p>I'm around for questions and such most of the time, though it's been a while since I looked into this</p>



<a name="177257419"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257419" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257419">(Oct 03 2019 at 15:46)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="177257440"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257440" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257440">(Oct 03 2019 at 15:46)</a>:</h4>
<p>yeah I was going to ask if you had any thought in general</p>



<a name="177257453"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257453" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257453">(Oct 03 2019 at 15:46)</a>:</h4>
<p>first I'm starting to check how the tool works</p>



<a name="177257523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257523">(Oct 03 2019 at 15:47)</a>:</h4>
<p>Yeah so there's two parts to any bisection tool:</p>
<ul>
<li>getting the "artifacts" (in our case, rustc binaries)</li>
<li>actual bisection bit</li>
</ul>



<a name="177257555"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257555" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257555">(Oct 03 2019 at 15:47)</a>:</h4>
<p>the actual bisection bit is actually not a trivial algorithm, particularly as we want to do so without actually knowing all of the points</p>



<a name="177257620"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257620" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257620">(Oct 03 2019 at 15:48)</a>:</h4>
<p>it's also (AFAICT) a literally not possible problem, we have to use heuristics, for our case</p>



<a name="177257691"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257691" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257691">(Oct 03 2019 at 15:49)</a>:</h4>
<blockquote>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <span class="user-mention silent" data-user-id="116122">simulacrum</span> FYI I'm going to take this task slowly meanwhile I'm doing other things</p>
</blockquote>
<p>I've created this <a href="https://github.com/spastorino/cargo-bisect-sample" target="_blank" title="https://github.com/spastorino/cargo-bisect-sample">https://github.com/spastorino/cargo-bisect-sample</a> as a sample app so it's easier to play with this tool and in particular it helps to build more automation around cargo-bisect-rustc</p>



<a name="177257693"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177257693" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177257693">(Oct 03 2019 at 15:49)</a>:</h4>
<p>now yes :)</p>



<a name="177258465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177258465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177258465">(Oct 03 2019 at 15:58)</a>:</h4>
<blockquote>
<p>it's also (AFAICT) a literally not possible problem, we have to use heuristics, for our case</p>
</blockquote>
<p>To elaborate on this a bit...</p>
<p>We don't generally know what a given result means. In particular, say we have compilers A B C D E (ordered by ~time). A given crate may work on A, C, E due to unrelated breakage in B and D. This means that when bisecting, we don't know whether a bad result means we've reached an edge and should go the other way, or if we're just in the middle somewhere.</p>



<a name="177258504"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177258504" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177258504">(Oct 03 2019 at 15:58)</a>:</h4>
<p>This can also be thought of as the problem that bisection only truly works on a monotonic graph -- you need to only go from broken to working or working to broken at most once</p>



<a name="177258744"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177258744" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177258744">(Oct 03 2019 at 16:00)</a>:</h4>
<p>The main pain point with cargo bisect rustc from a usability perspective is that it is rather hard to determine what the user wants, and talking about the range you want to bisect over is also not really easy: what does "start" or "end" mean? If it's seen temporally, e.g. start is 2019-01-01 and end is today, then it's a bit weird that the first thing we'll test is today's nightly</p>



<a name="177258792"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177258792" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177258792">(Oct 03 2019 at 16:01)</a>:</h4>
<p>anyway this is all mostly a bit of a brain dump right now :)</p>



<a name="177258816"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177258816" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177258816">(Oct 03 2019 at 16:01)</a>:</h4>
<p>I can try to answer specific questions -- probably easier to deal with than my saying lots of things</p>



<a name="177259979"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177259979" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177259979">(Oct 03 2019 at 16:13)</a>:</h4>
<p>yeah, I understand what you meant</p>



<a name="177260018"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177260018" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177260018">(Oct 03 2019 at 16:13)</a>:</h4>
<p>I guess in a tool like this there should be some premises that may not hold on projects and at that point the tool may not work correctly</p>



<a name="177260128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177260128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177260128">(Oct 03 2019 at 16:14)</a>:</h4>
<p>but I guess it would be sane to assume that you provide a start and an end and there's only one point of failure in between or else the tool may not work</p>



<a name="177260156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177260156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177260156">(Oct 03 2019 at 16:15)</a>:</h4>
<p>we could even start from the last nightly assuming that that's the not working version and going back until there's one that works</p>



<a name="177260183"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177260183" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177260183">(Oct 03 2019 at 16:15)</a>:</h4>
<p>but again, always assuming that there's just one failure between those two points</p>



<a name="177260190"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177260190" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177260190">(Oct 03 2019 at 16:15)</a>:</h4>
<p>and it's the one you're looking for</p>



<a name="177261403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177261403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177261403">(Oct 03 2019 at 16:28)</a>:</h4>
<p>Right. I personally think we might want to give up on bisection for the common case -- just linear scan</p>



<a name="177261428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177261428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177261428">(Oct 03 2019 at 16:28)</a>:</h4>
<p>linear scan is plenty fast if we're doing so recently</p>



<a name="177270079"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270079" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270079">(Oct 03 2019 at 18:02)</a>:</h4>
<p>is part of the plan here to make <code>rustc-bisect</code> able to do its own local builds, to get a finer grain than what the CI nightlies provide?</p>



<a name="177270116"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270116" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270116">(Oct 03 2019 at 18:02)</a>:</h4>
<p>(because there are additional pain points I would anticipate in automating that process, especially if you do not do clean checkouts+builds in between each run)</p>



<a name="177270766"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270766" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270766">(Oct 03 2019 at 18:09)</a>:</h4>
<p>hm, I think I would say at this point no</p>



<a name="177270774"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270774" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270774">(Oct 03 2019 at 18:09)</a>:</h4>
<p>since 'random person' does not want to compile rustc</p>



<a name="177270802"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270802" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270802">(Oct 03 2019 at 18:09)</a>:</h4>
<p>and bisecting between two rustc bors commits is usually not too hard for a compiler dev</p>



<a name="177270874"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270874" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270874">(Oct 03 2019 at 18:10)</a>:</h4>
<p>another pain point is looking for the absence of some output (a warning, or a specific error), grep -v does not help here</p>



<a name="177270927"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270927" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270927">(Oct 03 2019 at 18:10)</a>:</h4>
<p>one thought I have had is to run things with rendered-ansi mode and basically UI test it</p>



<a name="177270945"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177270945" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177270945">(Oct 03 2019 at 18:11)</a>:</h4>
<p>it's a bit error prone but maybe having a "collection of allowed outputs" vs. just one is viable there</p>



<a name="177271000"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177271000" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177271000">(Oct 03 2019 at 18:11)</a>:</h4>
<p>I guess those are orthogonal -- I was imagining that we could have a mode for "I want this error code emitted", and another with the UI testing</p>



<a name="177271543"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177271543" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177271543">(Oct 03 2019 at 18:17)</a>:</h4>
<p>until then I will make a PR to the tutorial to add the git log command to list bors' commits inside a date range, not a big deal but at least can save someone else a couple minutes looking for that</p>



<a name="177271581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177271581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177271581">(Oct 03 2019 at 18:17)</a>:</h4>
<p>indeed</p>



<a name="177301946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177301946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177301946">(Oct 04 2019 at 00:52)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> leaving this as a draft we can use to define goals and tasks</p>



<a name="177301949"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177301949" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177301949">(Oct 04 2019 at 00:52)</a>:</h4>
<p><a href="https://hackmd.io/Ipu9wSL4SCyx9_adR6GKLg" target="_blank" title="https://hackmd.io/Ipu9wSL4SCyx9_adR6GKLg">https://hackmd.io/Ipu9wSL4SCyx9_adR6GKLg</a></p>



<a name="177360939"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177360939" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177360939">(Oct 04 2019 at 17:24)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> about <a href="https://hackmd.io/Ipu9wSL4SCyx9_adR6GKLg" target="_blank" title="https://hackmd.io/Ipu9wSL4SCyx9_adR6GKLg">https://hackmd.io/Ipu9wSL4SCyx9_adR6GKLg</a> that we were talking about</p>



<a name="177360957"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177360957" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177360957">(Oct 04 2019 at 17:25)</a>:</h4>
<p>in particular the tasking</p>



<a name="177361002"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361002" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361002">(Oct 04 2019 at 17:25)</a>:</h4>
<p>first of all I was wondering about the <code>Use currently installed nightly as end point</code></p>



<a name="177361025"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361025" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361025">(Oct 04 2019 at 17:25)</a>:</h4>
<p>I think that's probably ok if the users has nightly as the default toolchain</p>



<a name="177361071"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361071" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361071">(Oct 04 2019 at 17:26)</a>:</h4>
<p>but what if the default is stable and there's one or two nightlies?</p>



<a name="177361077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361077">(Oct 04 2019 at 17:26)</a>:</h4>
<p>should we discover one?</p>



<a name="177361097"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361097" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361097">(Oct 04 2019 at 17:26)</a>:</h4>
<p>I think no</p>



<a name="177361107"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361107" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361107">(Oct 04 2019 at 17:26)</a>:</h4>
<p>should we just have a prerequisite of or do have a nightly version as default toolchain or please provide an end point</p>



<a name="177361108"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361108">(Oct 04 2019 at 17:26)</a>:</h4>
<p>that's both hard and not really helpful</p>



<a name="177361114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361114">(Oct 04 2019 at 17:26)</a>:</h4>
<p>yeah I think so</p>



<a name="177361124"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361124" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361124">(Oct 04 2019 at 17:26)</a>:</h4>
<p>I left some notes in the doc</p>



<a name="177361132"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361132" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361132">(Oct 04 2019 at 17:27)</a>:</h4>
<p>I guess I'd go with if you provide an end, we use that one</p>



<a name="177361147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361147">(Oct 04 2019 at 17:27)</a>:</h4>
<p>otherwise the default toolchain is used</p>



<a name="177361170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361170">(Oct 04 2019 at 17:27)</a>:</h4>
<p>whatever is that default toolchain</p>



<a name="177361185"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361185" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361185">(Oct 04 2019 at 17:27)</a>:</h4>
<p>but it would abort if the start is newer than that one</p>



<a name="177361212"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361212" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361212">(Oct 04 2019 at 17:27)</a>:</h4>
<p>I would personally say actually that we don't accept the end toolchain in anyway except for the default one in the current environment</p>



<a name="177361216"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361216" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361216">(Oct 04 2019 at 17:27)</a>:</h4>
<p>you may want to look for a regression you're hitting on stable I guess</p>



<a name="177361277"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361277" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361277">(Oct 04 2019 at 17:28)</a>:</h4>
<blockquote>
<p>I would personally say actually that we don't accept the end toolchain in anyway except for the default one in the current environment</p>
</blockquote>
<p>that's exactly what I'm saying, right? :)</p>



<a name="177361289"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361289" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361289">(Oct 04 2019 at 17:28)</a>:</h4>
<p>my english is ungreat and from time to time I need to recheck obvious things :)</p>



<a name="177361294"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361294" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361294">(Oct 04 2019 at 17:28)</a>:</h4>
<p>ah, well, "I guess I'd go with if you provide an end, we use that one" I interpreted as being you can provide it in other ways</p>



<a name="177361364"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361364" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361364">(Oct 04 2019 at 17:29)</a>:</h4>
<p>I meant, if you do from the command line end=2019-08-07 that one would be used</p>



<a name="177361366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361366">(Oct 04 2019 at 17:29)</a>:</h4>
<p>to be clear this means that the expected workflow is strictly that you start by doing <code>cargo +toolchain check</code>, this fails. So before you file a bug report, you run <code>cargo +toolchain bisect-rustc</code> and that'll look for the first successful nightly/SHA going backwards in time.</p>



<a name="177361439"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361439" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361439">(Oct 04 2019 at 17:30)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="177361441"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361441" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361441">(Oct 04 2019 at 17:30)</a>:</h4>
<p>so I'm saying that we would scale back and not provide nearly as many CLI flags -- or maybe "hide" them behind some advanced interface</p>



<a name="177361455"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361455" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361455">(Oct 04 2019 at 17:30)</a>:</h4>
<p>yep agreed</p>



<a name="177361468"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361468" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361468">(Oct 04 2019 at 17:30)</a>:</h4>
<p>I think it makes a lot of sense to make the tool be sort of intelligent but overall pretty 'not tunable' at least initially</p>



<a name="177361487"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361487" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361487">(Oct 04 2019 at 17:31)</a>:</h4>
<p>what do you mean by not tunable?</p>



<a name="177361498"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361498" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361498">(Oct 04 2019 at 17:31)</a>:</h4>
<p>i.e. not too many options, does basically the same thing everytime</p>



<a name="177361572"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361572" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361572">(Oct 04 2019 at 17:32)</a>:</h4>
<p>ok</p>



<a name="177361634"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177361634" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177361634">(Oct 04 2019 at 17:32)</a>:</h4>
<p>to be clear I think we can issue breaking changes without a problem here at this point</p>



<a name="177365390"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365390" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365390">(Oct 04 2019 at 18:17)</a>:</h4>
<p>hey back, sorry went to have lunch</p>



<a name="177365402"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365402" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365402">(Oct 04 2019 at 18:17)</a>:</h4>
<p>next about <code>Find a starting point going exponentially backwards</code></p>



<a name="177365435"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365435" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365435">(Oct 04 2019 at 18:17)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> you added a comment there saying what the tool currently does</p>



<a name="177365441"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365441" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365441">(Oct 04 2019 at 18:17)</a>:</h4>
<p>but I'm a bit confused here</p>



<a name="177365501"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365501" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365501">(Oct 04 2019 at 18:18)</a>:</h4>
<p>the tool works by using a start and end and does what you say</p>



<a name="177365530"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365530" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365530">(Oct 04 2019 at 18:18)</a>:</h4>
<p>in this case we would be looking for a working version</p>



<a name="177365597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365597">(Oct 04 2019 at 18:19)</a>:</h4>
<p>unsure if the best way to search would be the same in these cases</p>



<a name="177365609"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365609" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365609">(Oct 04 2019 at 18:19)</a>:</h4>
<p>ah yes you are right</p>



<a name="177365619"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365619" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365619">(Oct 04 2019 at 18:19)</a>:</h4>
<p>unsure I got exactly the meaning of your comments</p>



<a name="177365620"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365620" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365620">(Oct 04 2019 at 18:19)</a>:</h4>
<p>ah ok</p>



<a name="177365625"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365625" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365625">(Oct 04 2019 at 18:19)</a>:</h4>
<p>I was remembering wrong and the exact handling is wrong</p>



<a name="177365637"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365637" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365637">(Oct 04 2019 at 18:19)</a>:</h4>
<p>er, is complicated and probably wrong</p>



<a name="177365659"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365659" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365659">(Oct 04 2019 at 18:20)</a>:</h4>
<p>what is wrong sorry?</p>



<a name="177365884"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177365884" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177365884">(Oct 04 2019 at 18:22)</a>:</h4>
<p>ah my reasoning</p>



<a name="177366258"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177366258" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177366258">(Oct 04 2019 at 18:26)</a>:</h4>
<p>I still wonder what's the best way to go back</p>



<a name="177366308"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177366308" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177366308">(Oct 04 2019 at 18:27)</a>:</h4>
<p>isn't maybe nice to try first with the latest available stable?</p>



<a name="177366421"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177366421" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177366421">(Oct 04 2019 at 18:28)</a>:</h4>
<p>I meant, you want to quickly find a working version in this phase</p>



<a name="177366454"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177366454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177366454">(Oct 04 2019 at 18:28)</a>:</h4>
<p>of course you don't want to start from version 1.0 or a previous one :P</p>



<a name="177366530"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177366530" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177366530">(Oct 04 2019 at 18:29)</a>:</h4>
<p>and if that fails maybe keep jumping through stables?</p>



<a name="177367073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367073">(Oct 04 2019 at 18:35)</a>:</h4>
<p>I would not do that, it's error prone</p>



<a name="177367085"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367085" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367085">(Oct 04 2019 at 18:35)</a>:</h4>
<p>it is fairly fast and effective to do the 2x backwards that I suggested</p>



<a name="177367171"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367171">(Oct 04 2019 at 18:36)</a>:</h4>
<p>this does [today; 2 days ago; 4 days ago; 8 days ago; 16 days ago; 1 month ago; 2 months ago] -- that's 7 hops max for most new things</p>



<a name="177367178"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367178" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367178">(Oct 04 2019 at 18:36)</a>:</h4>
<p>and most likely it'll be within the first couple</p>



<a name="177367211"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367211" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367211">(Oct 04 2019 at 18:36)</a>:</h4>
<p>you could even be more aggressive and start 1 day ago -&gt; 4 days ago  -&gt; 8 days ago -&gt; 16 days ago</p>



<a name="177367282"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367282" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367282">(Oct 04 2019 at 18:37)</a>:</h4>
<p>(fwiw, everything that's in the hackmd looks great to me, and I agree that avoiding a checkout is good if we can do it)</p>



<a name="177367363"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367363" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367363">(Oct 04 2019 at 18:38)</a>:</h4>
<p>stepping back 1 day, 2, 4 etc is exactly what I had in mind</p>



<a name="177367446"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367446" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367446">(Oct 04 2019 at 18:39)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="177367740"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367740" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367740">(Oct 04 2019 at 18:42)</a>:</h4>
<blockquote>
<p>(fwiw, everything that's in the hackmd looks great to me, and I agree that avoiding a checkout is good if we can do it)</p>
</blockquote>
<p>now about this ^^^</p>



<a name="177367745"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367745" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367745">(Oct 04 2019 at 18:42)</a>:</h4>
<div class="codehilite"><pre><span></span>    - I would avoid a checkout here, it&#39;s pretty expensive disk space/network and quite slow
    - We can either query GitHub API or I would not mind us running a Rust server somewhere on rust infra for this
</pre></div>



<a name="177367755"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367755" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367755">(Oct 04 2019 at 18:42)</a>:</h4>
<p>what would be the idea then?</p>



<a name="177367808"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367808" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367808">(Oct 04 2019 at 18:43)</a>:</h4>
<p>you query Github API and get a range of PRs and after that?</p>



<a name="177367833"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367833" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367833">(Oct 04 2019 at 18:43)</a>:</h4>
<p>unsure either what you meant by having a Rust server</p>



<a name="177367929"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177367929" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177367929">(Oct 04 2019 at 18:44)</a>:</h4>
<p>are you suggesting that in order to use this the user should already have a rustc copy around?</p>



<a name="177369138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369138">(Oct 04 2019 at 18:57)</a>:</h4>
<p>ah so you should not need a checkout</p>



<a name="177369147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369147">(Oct 04 2019 at 18:58)</a>:</h4>
<p>a checkout is pretty heavy</p>



<a name="177369195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369195">(Oct 04 2019 at 18:58)</a>:</h4>
<p>we can query the github API for everything we could get from the checkout</p>



<a name="177369220"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369220" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369220">(Oct 04 2019 at 18:58)</a>:</h4>
<p>or, if that's hard or slow, I meant we could have an HTTP server that helps out bisectors by providing helpful and not-really-rate limited endpoints</p>



<a name="177369270"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369270" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369270">(Oct 04 2019 at 18:59)</a>:</h4>
<p>internally this could either go to github API or reference local github repo or something</p>



<a name="177369279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369279">(Oct 04 2019 at 18:59)</a>:</h4>
<p>but I meant, unsure if we are talking about the same thing</p>



<a name="177369291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369291">(Oct 04 2019 at 18:59)</a>:</h4>
<p>once you found that the regression happened on nightly-X-Y-Z</p>



<a name="177369342"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369342" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369342">(Oct 04 2019 at 19:00)</a>:</h4>
<p>you may want to find the rustc commit that've caused the problem</p>



<a name="177369402"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369402" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369402">(Oct 04 2019 at 19:00)</a>:</h4>
<p>with Github API we can find a set of commits where the culprit is included</p>



<a name="177369420"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369420" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369420">(Oct 04 2019 at 19:01)</a>:</h4>
<p>but in order to know which one is it we need to bisect through them</p>



<a name="177369428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369428">(Oct 04 2019 at 19:01)</a>:</h4>
<p>still that's what the tool already does</p>



<a name="177369435"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369435" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369435">(Oct 04 2019 at 19:01)</a>:</h4>
<p>maybe that's what you meant</p>



<a name="177369501"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369501" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369501">(Oct 04 2019 at 19:02)</a>:</h4>
<p>all what new code needs to do is find start and end commits and call the existing bisect function</p>



<a name="177369515"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369515" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369515">(Oct 04 2019 at 19:02)</a>:</h4>
<p>so the code would check Github and all that</p>



<a name="177369523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177369523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177369523">(Oct 04 2019 at 19:02)</a>:</h4>
<p>if that's what you meant agree :)</p>



<a name="177370667"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177370667" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177370667">(Oct 04 2019 at 19:19)</a>:</h4>
<p>yes, that's basically it</p>



<a name="177370682"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177370682" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177370682">(Oct 04 2019 at 19:19)</a>:</h4>
<p>we already have full commits from nightlies for start/end so we just need a list of commits</p>



<a name="177370745"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177370745" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177370745">(Oct 04 2019 at 19:20)</a>:</h4>
<p>also</p>



<a name="177370777"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177370777" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177370777">(Oct 04 2019 at 19:20)</a>:</h4>
<p>can't we just take sha's from the nightlies?</p>



<a name="177370796"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177370796" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177370796">(Oct 04 2019 at 19:20)</a>:</h4>
<p>there's no need to go to github api</p>



<a name="177370838"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177370838" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177370838">(Oct 04 2019 at 19:21)</a>:</h4>
<p>I meant the range in which we can look for a PR is ... the good nigthly and the bad nightly that's next to it</p>



<a name="177371248"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177371248" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177371248">(Oct 04 2019 at 19:27)</a>:</h4>
<p>right</p>



<a name="177371268"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177371268" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177371268">(Oct 04 2019 at 19:27)</a>:</h4>
<p>but to get the per-SHA artifacts you need to enumerate SHAs inbetween those</p>



<a name="177371279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177371279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177371279">(Oct 04 2019 at 19:27)</a>:</h4>
<p>that requires API</p>



<a name="177372824"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177372824" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177372824">(Oct 04 2019 at 19:44)</a>:</h4>
<p>but isn't that we the tool already does?</p>



<a name="177373087"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177373087" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177373087">(Oct 04 2019 at 19:47)</a>:</h4>
<p>right yeah we have that logic already</p>



<a name="177373416"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177373416" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177373416">(Oct 04 2019 at 19:50)</a>:</h4>
<p>so ... there's nothing we need to add then in that regard :)</p>



<a name="177373463"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177373463" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177373463">(Oct 04 2019 at 19:51)</a>:</h4>
<p>well the last thing may be bisecting within the PR</p>



<a name="177373483"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177373483" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177373483">(Oct 04 2019 at 19:51)</a>:</h4>
<p>I guess the tool doesn't do that currently, right?</p>



<a name="177376204"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376204" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376204">(Oct 04 2019 at 20:28)</a>:</h4>
<div class="codehilite"><pre><span></span>- Bisect on beta/stable
    - go to &#39;real&#39; nightly by looking at version and looking up appropriate branch point nightly
    - e.g. for 1.39 (currently in beta) branched on September 26th 2019 (date of 1.38 release, ~easily computable with 6 week offsets)
    - so you&#39;d want nightly-2019-09-27 (this is not perfect, but good enough)
</pre></div>



<a name="177376220"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376220" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376220">(Oct 04 2019 at 20:28)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> I'm not sure what that means ^^^</p>



<a name="177376257"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376257" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376257">(Oct 04 2019 at 20:29)</a>:</h4>
<p>bisecting within a single PR is not tenable for anyone not a compiler dev, you need to build the compiler, this tool will not support that</p>



<a name="177376281"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376281" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376281">(Oct 04 2019 at 20:29)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> I was proposing a way to bisect into nightlies when given a beta build as the default</p>



<a name="177376297"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376297" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376297">(Oct 04 2019 at 20:30)</a>:</h4>
<p>you can sort of "unwrap" a beta to get the nightly when it branched</p>



<a name="177376373"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376373" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376373">(Oct 04 2019 at 20:30)</a>:</h4>
<p>but this is pretty far future, I wouldn't worry about it too much for now</p>



<a name="177376389"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376389" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376389">(Oct 04 2019 at 20:30)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="177376424"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376424" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376424">(Oct 04 2019 at 20:31)</a>:</h4>
<p>thank you very much for helping me plan this :)</p>



<a name="177376549"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376549" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376549">(Oct 04 2019 at 20:32)</a>:</h4>
<p>sure thing</p>



<a name="177376555"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/rustc-bisect/near/177376555" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/rustc-bisect.html#177376555">(Oct 04 2019 at 20:32)</a>:</h4>
<p>gets me off of doing it eventually :)</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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